src/dev/mc146818.cc

   1 /*
   2  * Copyright (c) 2004-2005 The Regents of The University of Michigan
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are
   7  * met: redistributions of source code must retain the above copyright
   8  * notice, this list of conditions and the following disclaimer;
   9  * redistributions in binary form must reproduce the above copyright
  10  * notice, this list of conditions and the following disclaimer in the
  11  * documentation and/or other materials provided with the distribution;
  12  * neither the name of the copyright holders nor the names of its
  13  * contributors may be used to endorse or promote products derived from
  14  * this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  17  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  18  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  19  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  20  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  21  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  22  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  26  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  *
  28  * Authors: Ali Saidi
  29  *          Andrew Schultz
  30  *          Miguel Serrano
  31  */
  32
  33 #include <sys/time.h>
  34
  35 #include <ctime>
  36 #include <string>
  37
  38 #include "base/bitfield.hh"
  39 #include "base/time.hh"
  40 #include "base/trace.hh"
  41 #include "debug/MC146818.hh"
  42 #include "dev/mc146818.hh"
  43 #include "dev/rtcreg.h"
  44
  45 using namespace std;
  46
  47 static uint8_t
  48 bcdize(uint8_t val)
  49 {
  50     uint8_t result;
  51     result = val % 10;
  52     result += (val / 10) << 4;
  53     return result;
  54 }
  55
  56 static uint8_t
  57 unbcdize(uint8_t val)
  58 {
  59     uint8_t result;
  60     result = val & 0xf;
  61     result += (val >> 4) * 10;
  62     return result;
  63 }
  64
  65 void
  66 MC146818::setTime(const struct tm time)
  67 {
  68     curTime = time;
  69     year = time.tm_year;
  70     // Unix is 0-11 for month, data seet says start at 1
  71     mon = time.tm_mon + 1;
  72     mday = time.tm_mday;
  73     hour = time.tm_hour;
  74     min = time.tm_min;
  75     sec = time.tm_sec;
  76
  77     // Datasheet says 1 is sunday
  78     wday = time.tm_wday + 1;
  79
  80     if (!(stat_regB & RTCB_BIN)) {
  81         // The datasheet says that the year field can be either BCD or
  82         // years since 1900.  Linux seems to be happy with years since
  83         // 1900.
  84         year = bcdize(year % 100);
  85         mon = bcdize(mon);
  86         mday = bcdize(mday);
  87         hour = bcdize(hour);
  88         min = bcdize(min);
  89         sec = bcdize(sec);
  90     }
  91 }
  92
  93 MC146818::MC146818(EventManager *em, const string &n, const struct tm time,
  94                    bool bcd, Tick frequency)
  95     : EventManager(em), _name(n), event(this, frequency), tickEvent(this)
  96 {
  97     memset(clock_data, 0, sizeof(clock_data));
  98     stat_regA = RTCA_32768HZ | RTCA_1024HZ;
  99     stat_regB = RTCB_PRDC_IE | RTCB_24HR;
 100     if (!bcd)
 101         stat_regB |= RTCB_BIN;
 102
 103     setTime(time);
 104     DPRINTFN("Real-time clock set to %s", asctime(&time));
 105 }
 106
 107 MC146818::~MC146818()
 108 {
 109     deschedule(tickEvent);
 110     deschedule(event);
 111 }
 112
 113 void
 114 MC146818::writeData(const uint8_t addr, const uint8_t data)
 115 {
 116     if (addr < RTC_STAT_REGA) {
 117         clock_data[addr] = data;
 118         curTime.tm_sec = unbcdize(sec);
 119         curTime.tm_min = unbcdize(min);
 120         curTime.tm_hour = unbcdize(hour);
 121         curTime.tm_mday = unbcdize(mday);
 122         curTime.tm_mon = unbcdize(mon) - 1;
 123         curTime.tm_year = ((unbcdize(year) + 50) % 100) + 1950;
 124         curTime.tm_wday = unbcdize(wday) - 1;
 125     } else {
 126         switch (addr) {
 127           case RTC_STAT_REGA:
 128             // The "update in progress" bit is read only.
 129             if ((data & ~RTCA_UIP) != (RTCA_32768HZ | RTCA_1024HZ))
 130                 panic("Unimplemented RTC register A value write!\n");
 131             replaceBits(stat_regA, data, 6, 0);
 132             break;
 133           case RTC_STAT_REGB:
 134             if ((data & ~(RTCB_PRDC_IE | RTCB_SQWE)) != RTCB_24HR)
 135                 panic("Write to RTC reg B bits that are not implemented!\n");
 136
 137             if (data & RTCB_PRDC_IE) {
 138                 if (!event.scheduled())
 139                     event.scheduleIntr();
 140             } else {
 141                 if (event.scheduled())
 142                     deschedule(event);
 143             }
 144             stat_regB = data;
 145             break;
 146           case RTC_STAT_REGC:
 147           case RTC_STAT_REGD:
 148             panic("RTC status registers C and D are not implemented.\n");
 149             break;
 150         }
 151     }
 152 }
 153
 154 uint8_t
 155 MC146818::readData(uint8_t addr)
 156 {
 157     if (addr < RTC_STAT_REGA)
 158         return clock_data[addr];
 159     else {
 160         switch (addr) {
 161           case RTC_STAT_REGA:
 162             // toggle UIP bit for linux
 163             stat_regA ^= RTCA_UIP;
 164             return stat_regA;
 165             break;
 166           case RTC_STAT_REGB:
 167             return stat_regB;
 168             break;
 169           case RTC_STAT_REGC:
 170           case RTC_STAT_REGD:
 171             return 0x00;
 172             break;
 173           default:
 174             panic("Shouldn't be here");
 175         }
 176     }
 177 }
 178
 179 void
 180 MC146818::tickClock()
 181 {
 182     if (stat_regB & RTCB_NO_UPDT)
 183         return;
 184     time_t calTime = mkutctime(&curTime);
 185     calTime++;
 186     setTime(*gmtime(&calTime));
 187 }
 188
 189 void
 190 MC146818::serialize(const string &base, ostream &os)
 191 {
 192     arrayParamOut(os, base + ".clock_data", clock_data, sizeof(clock_data));
 193     paramOut(os, base + ".stat_regA", stat_regA);
 194     paramOut(os, base + ".stat_regB", stat_regB);
 195
 196     //
 197     // save the timer tick and rtc clock tick values to correctly reschedule
 198     // them during unserialize
 199     //
 200     Tick rtcTimerInterruptTickOffset = event.when() - curTick();
 201     SERIALIZE_SCALAR(rtcTimerInterruptTickOffset);
 202     Tick rtcClockTickOffset = tickEvent.when() - curTick();
 203     SERIALIZE_SCALAR(rtcClockTickOffset);
 204 }
 205
 206 void
 207 MC146818::unserialize(const string &base, Checkpoint *cp,
 208                       const string &section)
 209 {
 210     arrayParamIn(cp, section, base + ".clock_data", clock_data,
 211                  sizeof(clock_data));
 212     paramIn(cp, section, base + ".stat_regA", stat_regA);
 213     paramIn(cp, section, base + ".stat_regB", stat_regB);
 214
 215     //
 216     // properly schedule the timer and rtc clock events
 217     //
 218     Tick rtcTimerInterruptTickOffset;
 219     UNSERIALIZE_SCALAR(rtcTimerInterruptTickOffset);
 220     reschedule(event, curTick() + rtcTimerInterruptTickOffset);
 221     Tick rtcClockTickOffset;
 222     UNSERIALIZE_SCALAR(rtcClockTickOffset);
 223     reschedule(tickEvent, curTick() + rtcClockTickOffset);
 224 }
 225
 226 MC146818::RTCEvent::RTCEvent(MC146818 * _parent, Tick i)
 227     : parent(_parent), interval(i)
 228 {
 229     DPRINTF(MC146818, "RTC Event Initilizing\n");
 230     parent->schedule(this, curTick() + interval);
 231 }
 232
 233 void
 234 MC146818::RTCEvent::scheduleIntr()
 235 {
 236     parent->schedule(this, curTick() + interval);
 237 }
 238
 239 void
 240 MC146818::RTCEvent::process()
 241 {
 242     DPRINTF(MC146818, "RTC Timer Interrupt\n");
 243     parent->schedule(this, curTick() + interval);
 244     parent->handleEvent();
 245 }
 246
 247 const char *
 248 MC146818::RTCEvent::description() const
 249 {
 250     return "RTC interrupt";
 251 }
 252
 253 void
 254 MC146818::RTCTickEvent::process()
 255 {
 256     DPRINTF(MC146818, "RTC clock tick\n");
 257     parent->schedule(this, curTick() + SimClock::Int::s);
 258     parent->tickClock();
 259 }
 260
 261 const char *
 262 MC146818::RTCTickEvent::description() const
 263 {
 264     return "RTC clock tick";
 265 }